add a IDE generator for clang json database format

This can be used for YouCompleteMe a vim plugin that allows
auto-completition based on clang. This is much better than the normal
static analyzer based auto-completition.

Change-Id: I4872d2cb3b3a404af55eacf5c71d6a2715771ab6
Reviewed-on: https://gerrit.libreoffice.org/10820
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
write directly files understood by YCM

Change-Id: I262050f625a0b3ff04a274c88b446d1c2b2aa19d
Reviewed-on: https://gerrit.libreoffice.org/10821
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>