Remove the server/ directory from .gitignore

The dist/ folder is already here for non-versioned code
Refactor the banner and the clean task
Refactor the concat task
Refactor the copy task
Refactor the express task
Refactor the jsdoc task
Refactor the open task and remove useless ones
Refactor the string-replace task
Refactor the watch task
Refactor the custom tasks
Refactor and reorganize the CSS a bit
Remove trailing whitespaces over source code
Refactor unit tests a bit, need to go further in refactoring

This is not exactly the way we should test as we don't reset the environment for each test, so we might have some regressions problems.
Still, this is not bad at all - GG @fabien0102 =)
Update README a bit - sentence correction
Change the version number
Compile v0.3.0 build
Compile v0.3.0 docs
Merge branch 'release/v0.3.0' into develop