init commit.
fix js error.
Accept a url parameter 'bars' that can change the number of bars created; default to 4 if no parameter is given
Add support for another url endpoint, /api/, that outputs the number of bars to be generated in JSON format: {num_bars: X}
      - The /api/ endpoint should also support a 'callback' parameter to specify a JSONP callback.
      - This should also support the 'bars' parameter above
Have the bars dynamically sized on the page so that they
      a) don't wrap around when there are too many
      b) fill the entire width of #bars when there are too few
      c) expand and contract dynamically with the page but without a pageload
make some security or performance enhancements as necessary
set max number of bars to 49 so that browser won't crash; PHP_INT_MAX is not a good option here.
Merge branch 'master' of github.com:liuwenchao/tx