git: .gitignore update

ignore all "dot" files/directories by default.
'ignored' files can be added via 'git add -f' command if necessary.

.gitignore

+# ignore dot files/directories
+.*
+!.gitignore
+
 *.autosave
 *.pyc
 *.user
 *~
-.*.swp
-.DS_Store
-.sw[a-z]
 tags
 tegra/
-.cache