merged current work
stylistic changes
use std vector instead of lists for transactions and undo_records
fixed in rvm_t and rvm_init
use vector for segments list and simplify map function
implemented transaction commit
implement abort transaction
Merge branch 'master' of github.com:netrakenkarey/RVM

Conflicts:
	rvm.cpp
	rvm.h
modified rvm_destroy to work with rest of the code
implemented segment recovery
fix segment recovery
implemented log truncation
added testcases, fixed bugs for basic test