refs #1654 : enhancement - automatic mobile skin load.

 - i/ and m/ URLs are removed.

From now on, textcube loads skin/blog/lucid when
  - blog.useiPhoneMode is true
  - device agent is recognized as the one of mobile devices.

TODO:
  - mobile <-> desktop mode button
  - move skin location to under resource/ directory.
  - upgrade skin parser to read skins outside /skin/blog directory.
  - Lots of mobile skin design / functions