[BUG_FIXED] (Author: Andreas Jonsson) Fix a bug in NppShell when trying to open many files.

git-svn-id: svn://svn.tuxfamily.org/svnroot/notepadplus/repository/trunk@1239 f5eea248-9336-0410-98b8-ebc06183d4e3
[BUG_FIXED] Fix SaveAll command hanging issue while session snapshot is enabled.
[CHANGE_BEHAVIOUR] Disable session snapshot while command line -nosession is used.

git-svn-id: svn://svn.tuxfamily.org/svnroot/notepadplus/repository/trunk@1240 f5eea248-9336-0410-98b8-ebc06183d4e3