#21 Make the "Fold" function language-/tag-specific

[froschbrocken]

In the "View" menu I can choose how many tree levels are expanded (Level 1 .. Level N). It would be great if this setting could be set for each language separately, and even better for each tag type. Use case: I often work with C files and the main thing I want to see in the list is their functions. However, sometimes I want to browse thruogh other tags as well (macros, function prototypes), but I do not want to have them all automatically expanded, since this would make the list quite long and confusing. Thus it would be great if each tag type could be configured whether it automatically expands or not.

Furthermore, the current state of the tree expansion for a file (using single file mode) should be saved if a different file is selected in order to be restored as soon as I select the original file again (without closing it in between). With the current release, the state gets lost when switching between different open files, it always gets reset to the configured Level (1, 2, N) state.