-rename anything to flatfile_xxx/FLATFILE_xxx
-fix update function
-add warnings for update function

emalloc never returns 0, so we can simplify the code paths.
also replace ecalloc with emalloc+memset, so that the latter can be inlined.

fix locks and reading
#i will extend the tests to guard on such failures

Use the the name 'flatfile' correctly so the handler support can be built now.
#I do not like the lock solution since a crashed php would leave the *lck
#file locked now.