fckeditor 5.x-2.1

Most of the bugs found in 5.x-2.1beta and 5.x-2.1beta2 have been fixed.
This module seems to be stable enough to finally mark it as a "stable" release.

Recent changes:

• fixed issues with switching from text to fckeditor in the toogle,
  all previous content within the body was lost
• FCKeditor now appears for super user even if "access fckeditor" permissions are not yet assigned.
  (the Advanced profile for authenticated users is assigned)
• fixed issues with Internet Explorer
  (Object required error when "rich text editor toggle" was set to false)
• fixed issues with invalid validation of excluded fields
  (numbers are also allowed in IDs)
• extended the global list of fields where FCKeditor shouldn't appear
• added possibility to define custom javascript configuration
• improved handling resizable fields when FCKeditor is disabled
• lots of other bugfixes and improvements