Add an API to allow custom "path filter callbacks" to be added.
Previously we allowed one path filtering function to exist called
`NERDTreeCustomIgnoreFilter`. This has been removed and replaced with an
API to allow any number of such functions to exist - via the new
`NERDTreeAddPathFilter()`
Expand the event system to have explicit Event objects and potentially
many Notifiers. Previously they was only one notifier and one (implied)
event.
A lot of this is stolen from #358.
NERDTree can now optionally ignore the dot at the beginning of hidden
filenames for sorting to show them next to normal files if
`g:NERDTreeSortHiddenFirst` is set to 0. (By default it's set to 1 to
preserve the current behavior.) This is just like what GNU ls does when
`LC_COLLATE` environment variable is set to `en_US`.
Allows the user to create or copy a nested node
in a single step with ma or mc, recursively
creating nested parent directories if needed, and
without throwing any errors if they already exist.
[Finishes #163, #34]
On some new versions of vim these files were being loaded before the
main NERD_tree.vim which was causing errors as dependencies werent
loaded in time. Move the classes into lib - so vim wont try to load them
until we tell it
