How to properly and for once reinstall PHP/Apache So I'm struggeling with this since a long time and I'd like to find a proper solution.

I have php5.4.. install and I want to upgrade to Php 7.

No matter how hard I'm trying to do it I can't seems to touch my goal.
I tried to remove php54 and other with homebrew, to remove it manually by command line, to overwrite it with new version nothing work. What ever Im doing when I type php -v I always end up with php5.4 :

Marjorie:~ Mawel$ php -v
PHP 5.4.45 (cli) (built: Sep  6 2015 20:56:23) 
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2014 Zend Technologies


So I'm asking my self have I messed up with my php/apache conf ? Shall I try a clean-install of my system and would it be efficient ? I don't know ! I'm kinda lost and really need some help even for comprehension (is there a reason I can't get rid of old php version ?)

Anything would be helpful 

Edit

So here is more information for answering the questions : 

Output of brew tap

Marjorie:~ Mawel$ brew tap
homebrew/dupes
homebrew/php
homebrew/versions


As of what I've tried with home brew : 
So here is step by step the idea : 

brew remove php54
brew install php70
brew link php70
Warning: Already linked: /usr/local/Cellar/php70/7.0.4


Lets add this information : 

Marjorie:~ Mawel$ sudo find ~/ -iname "php"
/Users/Mawel//Code/agencedevoyage/sos-partenaire/vendor/phpunit/php-code-coverage/tests/PHP
/Users/Mawel//Code/agencedevoyage/sos-partenaire/vendor/phpunit/phpunit/src/Util/PHP
/Users/Mawel//Code/agencedevoyage/vendor/phpunit/php-code-coverage/tests/PHP
/Users/Mawel//Code/agencedevoyage/vendor/phpunit/phpunit/src/Util/PHP
/Users/Mawel//Code/PHP
/Users/Mawel//Code/Site Perso/dev/vendor/phpunit/php-code-coverage/tests/PHP
/Users/Mawel//Code/Site Perso/dev/vendor/phpunit/phpunit/src/Util/PHP
/Users/Mawel//Documents/Cours/BTS SIO/Developpement/PHP
/Users/Mawel//Documents/Cours/BTS SIO/Developpement/web/php
/Users/Mawel//Library/Application Support/Sublime Text 3/Cache/PHP
/Users/Mawel//Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/IPython/html/static/components/codemirror/mode/php


And finally, my bash profile :

Marjorie:~ Mawel$ vi ~/.bash_profile

alias composer="php /usr/local/bin/composer.phar"
PATH="/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:$PATH"
export PATH
export PATH=~/.composer/vendor/bin:$PATH
export PATH="/usr/local/mysql/bin:$PATH"

source ~/.profile
The brew commands look ok. You have all the taps you need.
First of all since you're working with homebrew, I'd suggest the following two commands (let's start clean):

brew update &amp;&amp; brew cleanup


So we're sure that we're using the latest homebrew release and we cleanup all old formulas and leftovers.

From your PATH it looks like usr/bin (which is the standard Mac OS X path for binaries and executables) comes before usr/local/bin (the path in which homebrew links the Cellar).
As you might know, Mac OS X when looking for binaries/executables scans the PATH from top to bottom so if both usr/bin and usr/local/bin have the php executables, since usr/bin comes first in PATH, then Mac OS X will use the php version in such folder, ignoring the version in usr/local/bin (which, as instead, is our target).  

To make sure regarding which version Mac OS X is using, type in the Terminal

which php


and if the output is usr/bin, then Mac OS X is using its own version. 

The core indeed now is to change the PATH order in bash_profile, and make sure that usr/local/bin comes before usr/bin (it is clear now that we're forcing Mac OS X to use the homebrew version).

Once the changes have been done, restart your Mac and type in the Terminal

echo $PATH


This will display the entire PATH list so you can make sure everything's in the right order.
Now, finally, you can check using either

which php


or

php -v


which is the running version.