nit cleanup
imfile: move polling code to dedicated function

part of preparing for inotify
Merge branch 'master-imfile-2' into master-imfile

Conflicts:
	plugins/imfile/imfile.c
add check for inotify availability
imfile milestone: add wdmap inotify support structures

untested
imfile milestone: basic monitoring for exisiting file works

but does not handle overwrite (delete&re-create), also code cannot be
activated by user at the moment. Still incomplete.
imfile milestone: permit user to select polling/inotify mode

inotify still incomplete
Merge branch 'master' into master-imfile
Merge branch 'master' into master-imfile
imfile milestone: basic plumbing for handling directory notifications

We have the base support structures and get notifications. We do not yet
handle them.
imfile milestone: monitoring file creation basically works

but we need to sort out the fine detailsof async notification
imfile milestone: refactor file to dir association

we may have two different inodes with the same file name in processing
at the same time
imfile milestone: inotify mode works

... with essentially the same semantics as polling mode, e.g. no
wildcards are yet supported.
Do not double escape json control chars
doc: extending README, moving to RST format
doc: improve README & add contribution info
Made links clickable + spelling fix
Merge pull request #4 from otisg/patch-2

Made links clickable + spelling fix
doc: note that omprog's pipe never loses data
doc: fix broken link to global directive doc