Make these all go through .open() and pass in args to control the
behaviour. Deprecate the old `openSplit`, `openVSplit` and
`openInNewTab` methods and make them private.

This makes the API a lot cleaner - it was getting pretty messy in this
regard.

This allows users to specify whether each regex in NERDTreeIgnore should
apply to only files or only dirs.

This fixes #89.

First, set the tree parts regex appropriately depending on
g:NERDTreeDirArrows.

Second, fix an edge case when trying to edit a file like +foo where the
+ meant 'foo' was being interpreted as an arg to the :edit cmd

this gives users a chance to filter out nodes using whatever logic they
please

Just call these functions directly at the bottom of the nerdtree script.
This simplifies things and fixes #99.

It seems that some versions of vim done like the syntax of:
    function("foo")()

so refactor it slightly.

dont display quickhelp for a mapping if there is no text to display -
this prevents all the default mappings from being displayed under the
"custom mappings" section.

Add "scope" to it. This allows the user to specify that keymaps should
 apply to files/directories/bookmarks or everything. This will reduce
the amount of 'if empty(node)' checks that are done

create s:setCommonBufOptions() with the previously duplicated parts of
s:initNerdTreeInPlace() and s:createTreeWin()

this breaks the highlighting of the nerdtree buffer, and seems dodgy

Note that for directories, there is a trailing slash

Remove the NERDTreeStopInsert option and always activate the
functionality. If, later on, it becomes apparent that some people might
not want this functionality then we can re-add the option, but in the
meantime, simplify things by removing the option.

3bb112d916

When copying a node to a directory that's outside the current path, the
"parent" node doesn't really exist, so the code raised an error.

Some other changes causted previos commit to break the NERDTreeFind functionality
instead of fixing it. Reverting...

vimrc files(such as perdirvimrc) after BufRead.

Set curPathComponent to 0 correctly identify with indent level of node.

Shortening this line doesnt add anything to the UI (functionally
speaking), but removing frees up an extra line. Anyone who sets
NERDTreeMinimalUI probably uses the u/U mappings anyway.

Use \V for the updir text regex. Otherwise '..' is treated as a regex
rather than 2 literal dots.