Added support for secureTextEntry (passwords)

Added a secureTextEntry property. Enabling this property causes the
TextField to display the entered text as bullets.
Changed some property names to match conventions.

Changed m_pSecureTextEntry to m_bSecureTextEntry and renamed
getSecureTextEntry to isSecureTextEntry
Merge branch 'master' of https://github.com/MarcelBloemendaal/cocos2d-x into MarcelBloemendaal-master
fixed #2068: Fixing a compilation error on win32 since "•" couldn't be recognized by vs compiler.
fixed #2068: Updating source format.
fixed #2068: Tab ~> 4 spaces.
Merge pull request #2403 from dumganhar/iss2068-cctextfield-secure

fixed #2068: Adding a secureTextEntry property. Enabling this property causes the TextField to display the entered text as bullets.