Linux: Set writable path to "<user's home>/.config/<app name>"
Merge remote-tracking branch 'upstream/master'

Conflicts:
	cocos2dx/platform/linux/CCFileUtilsLinux.cpp
Linux: Set writable path to "<user's home>/.config/<app name>"
Merge remote-tracking branch 'upstream/master'
Restore codes of init m_strDefaultResRootPath
Read app name from /proc/self/exe
Set writable path to XDG_CONFIG_HOME if it exists.
Merge pull request #2343 from Yodesoft/master

fixed #2053: [Linux] Setting writable path to "<user's home>/.config/<app name>".