Fix invalid usage of Math.floor + simplify code

First:
Math.floor(3.2) -> 3
Math.floor(3.7) -> 3
Math.floor(-3.7) -> -4
Math.floor(-3.2) -> -4

Second:
3.2|0  -> 3
-3.2|0 -> -3

So, behaviour of these approaches are DIFFERENT on negative values. So:
http://stackoverflow.com/questions/596467/how-do-i-convert-a-number-to-an-integer-in-javascript

src/analyzer.c: simplified code.
src/library.js:
* Simplify code, potentially fix bugs with negative time values in many places.
* FIX bugs in handling of negative numbers in modf(), modff() and div()

Simplify code for other functions where we need integer part of floating-point number.
suppress unneeded benchmark notification
simplify other.test_emcc --help detection to try to fix it on windows
Merge branch 'incoming' of https://github.com/hamishwillee/emscripten into incoming
use text output for local doc builds, and make emcc --help read and print its docs
clean up emcc --help
add test for modf negatives
use |0 in utf code
Merge branch 'floor' of https://github.com/socketpair/emscripten into incoming

Conflicts:
	src/runtime.js
fix test_rounding
Addition of Module reference and cross linking to it from elsewhere. Removal from Interacting with code
Fixes to home page layout, size of inline code text, emcc final updates, improvements to tutorial and downloads