Upgrade can only be called if phpbrew is on - refs #171
Upgrade can get current php major version - refs #171
Upgrade can get latest minor version of a major version - refs #171
Upgrade can get current variants - refs #171
Mock phpbrew to not depend on external things
Upgrade installs newest minor version with same variants as current minor - refs #171
Use more generic functions
Upgrade can list ext-installed extensions - refs #171
Upgrade installs currently installed extentions to the new version - refs #171
Fixed tests executing real things
Upgrade command fully working - refs #171
Added upgrade command to the bash script - refs #171
Added upgrade virtual command
Inform user if already up-to-date - refs #171
Compiled phar
Use cliframework v1.5.* as 1.6 don't seem to work
Merge pull request #204 from chadrien/develop

Use cliframework v1.5.* as 1.6 doesn't seem to work
Upgrade script is not yet on user machine

Kinda forgot this detail ~~
Compile phar
Make use and switch able to take a major version as argument

If a major version is given as argument, use/switch will use the latest
available minor version of this major version

e.g.: You have php 5.5.6 and 5.5.9, `phpbrew use 5.5` will be
equivalent to `phpbrew use 5.5.9`