added statsfs patch from Роман Бородин
added CONTRIBUTORS file
forgot to add the function.sql file
started to rewrite, removed dependecy on shell/Perl
resulting a fictive number for free files and free blocks for now
added test cases
removed function.sql
changed return type of free/used functions (64-bit)
added some ideas how to get the table space location on runtime
Merge branch 'master' into statfs
added some OIDs to path code for the blocks free operation
some code rearrangments around statfs functions
some first results in statfs, but some sizes are weird, also PGDATA handling is missing
more realistic values for free disk blocks
improved statfs (symlink handling, handling of default PGDATA)