fix cache problems when inserting a new heading

- fix cache problems when inserting a new heading, together with multi line
	text (closes issue #116)

Conflicts:

	doc/orgguide.txt

update release dates

- add error message for missing dependencies (closes issue #59)

Conflicts:

	doc/org.txt

* fix completion menu popup that disappeared because of the usage of

	vim.command
* closes issue #48

* add documentation for customizing syntax highlighting

initial release

* install -D doesn't work on BSD based systems; migrate commands to i…

…nstall -d