events: revert back to the race condition to avoid deadlock, unlock scheduler when running event callback

Libedit deps fix

Configuration fix
-----------------

Situation:
----------

Currently there are three problems when configuring the sources:

1. When configuring with `--with-libedit=/is/somewhere/else` the header files location is not passed into appropriate translation units and the compilation fails on missing header file `histedit.h`.

2. Compilation fails with `--disable-daemon` and `--enable-utilities` because libedit is pulled by static dependencies of utilities but is not detected in the configuration because of disabled daemon.

3. Sources of  `knotc` are compiled with daemon but the resulting binary is only built(linked) when utilities are also enabled, because utilisties provide necessary static `libknotus.la`.

Solution:
---------

* Add missing `$(libedit_CFLAGS)` into `src/Makefile.am` on relevant places.
* Presence of libedit is checked when configuring with daemon **or** utilities.
* Changes in `src/Makefile.am` so that `libknotus.la` is built when `HAVE_DAEMON` or `HAVE_UTILS`. Utility `knotc` is compiled and built with `knotd`.

See merge request !529

Karel Slaný authored 8 years ago and Daniel Salzman committed 8 years ago

Application knotc should be built together with the daemon. Static
utilities library is built together with daemon and/or the utilities.

When configured with daemon enabled and utils disabled then the sources
were compiled but the executable has not been built.

Compilation failed on missing header files when configured with
--with-libedit=/is/somewhere/else .

See merge request !520

closes #424

contrib: add file&directory removal function, use safer readdir

Copied file and directory removal function (simulating "rm -rf $path") from libtap to contrib/. It replaces the custom function in src/knot/conf/base.c.

See merge request !527

CID #1358571

Optimized find operation with tracking element position in heap.
O(N) -> O(1).

close #451

The change set includes some refactoring, many bug fixes, and several
small UI improvements.