Make navbar collapse when browsing on mobile

Add bootstrap 2.3.1 and js plugin
Customized theme - attached bootstrap variable.less

Signed-off-by: Lincoln Lee <git@lincoln.hk>
Remove border when window width < 979px

Signed-off-by: Lincoln Lee <git@lincoln.hk>
Add Ubuntu font

Signed-off-by: Lincoln Lee <git@lincoln.hk>
Follow space consistency

Signed-off-by: Lincoln Lee <git@lincoln.hk>
Compile with less

Signed-off-by: Lincoln Lee <git@lincoln.hk>
Merge pull request #1 from linc01n/mobile_collapse_menu

Make navbar collapse when browsing on mobile