added -f to force builds and -g to ignore the global timestamp
fixed so that the thread count isn't reduced when broken nodes appears
fixed bug with file_touch under windows
added support for visual studio 11
Merge pull request #45 from oy/master

Added support for visual studio 11
added some more events during startup
added test using separate thread for stating nodes. increases paralellism during script parsing.
moved the stat functionallity of a node into a separate function
swapped around so that the c++ dependency checker checks the graph before it checks if a file exists on disk. helps when running a stat is slow.
splitted up the dep_cpp and the dep_search defered functions into two separate lists so you can see which one of those that takes the most time.
reduced the number of stats that are done during a build by saving the value from the dependency checking
Removed the file_exist function. Just use the file_timestamp instead.
cleaned up some code and added priorization of jobs. decreases the build time under certain situations when you have jobs that take uneven time to complete.
fixed issues with the stat-thread