LF normalization, routing bugfix + some more

Added a gitattributes file which makes cross platform development easier which allows github to automatically detect lineendings.

Added error message in index.php if mysql connection fails

Fixed routing so that emoncms can be run in a subdirectory, e.g. domain.com/emoncms. The routing did not take into account that it would send "/emoncms/user/register.json" for example, so the request would fail thus incorrect controller/view mapping due to the path.

Added some UX tweaks, such as the possibility to login/register by using the enter-button instead of having to click the button with the mousecursor (default form-behavior)

Updated theme to use minified bootstrap javascript and css which makes the page load smaller.