calling filereadable() on a FIFO file never terminates so we have to
check for them

invalid bookmarks now placed after a blank line at the bottom of the
bookmarks file

if invalid bookmarks are detected, an error is outputted which directs
the user to :help NERDTreeInvalidBookmarks, which had been added to the
help file in this commit

add a '^' and '$' to the end of the file matching pattern so it cant get
confused by buffer names that happen to be a substring of buffer we are
comparing against

previously the mouse handling function was not passing the needed
argument to the ActivateNode function

now if invalid bookmarks are detected, the offending lines are moved to
the bottom of the bookmarks file.

if the user tries to activate a bookmark that has become invalid after
it was read, that bookmark will be removed from the cache and put at the
bottom of the bookmarks file

This reverts commit 21601d9c3d.

Ok, so that copying command doesnt work for windows... it doesnt do
directories properly.

we dont need it to default to 1 anymore as that was a hack for windows,
but now that we handle windows paths properly we dont need it

when the user hits B and opens the bookmarks table, stick the cursor at
the top of it

this way feels cleaner

make the t/T on directory nodes open a fresh NERD tree for the selected
dir in a new tab, rather than a netrw.

doesnt work for paths with some screwed up chars in them

when opening a file in a new split (with the <tab> map) we were doing
the :split with a "silent" modifier. This meant that a swap existed and
input was required from the user, the script would just freeze up

highlighting was still broken for bookmarks that werent alphanumeric
w/underscores. Also, highlight the path parts of the bookmarks table as
"normal" so they dont demand as much attention

now the only rule is that they cant contain spaces

The tree filters for files/hidden-files/bookmarks now operate off tab
local variables which default to the global variables when a nerd tree
is initialised in the tab. Note: the file-filter already operated in
this way.

This means that each tree/tab has its own filter settings that are
initialised to the users preferences as specified by the global
variables, but can be altered independently of the other trees/tabs

We needed to change how the bookmark name caching was done to work with
the new path-display-string caching. It has now been merged into path
string caching.

when the path object is refreshed, force the display string to be
recalculated

if the bookmark wasnt cached in the tree an exception was being thrown
that wasnt caught

instead of using 2 options to specify the position of the tree, just use
NERDTreeWinPos and set it to "left", "right", "top", "bottom"