Started work under issue #57.

Logger is now reused while restarting. Strange behaviour while using
same file is fixed (right order of restart).
reset is replaced with connect
PQping binding is added, but it doesn't help to detect the problem
connection.
Fixed issue #57.

Now freeChecker thread tests connection on aliveness by sending trivial
sql query (exactly 'SELECT 1;'). 

To not generate heavy trafic there is new config parameter:
aliveCheckTime in msecs that tells over which time pool should test free
connections, it is optional parameter and set by default to 3 seconds.
Compilation fixes for other configurations.
Travis build file fix
Found the problem. Dub new package.json name is dub.json, DDT prefer
dub.json.
Merge branch 'master' of https://github.com/DSoftOut/pgator.git

Conflicts:
	dub.json
	source/server/server.d