Fix rendered characters have been chipped for some TrueType fonts

ImageFont ignores descender value of TrueType fonts (uses ascender only),
then some fonts which use descender is chipped on rendering.
Starting to integrate README
Rst, not gfm.
::block formatting
Merge branch 'master' of https://github.com/wiredfool/Pillow into readme
replaced tabs with space in _imaging.c
approximate test for lossy image writing
py3 as well
JpegImagePlugin sets bufsize for optimized images
Merge pull request #158 from wiredfool/maxblock

JpegImagePlugin sets bufsize for optimized images
Merge pull request #157 from wiredfool/webp_tests

approximate test for lossy image writing
Merge pull request #156 from homm/master

Performance improvement of alpha_composite function
Merge pull request #159 from homm/master

Precision of alpha composite. Again.
≈20% faster, 2 times more precisely (0.17% difference against 0.37%)
added tests to cover save of four different png transparencies
Merge branch 'master' of https://github.com/python-imaging/Pillow
Explitly import JpegPresets from the PIL package
Merge pull request #163 from ronaldoussoren/master

Issue 161: import JpegPresets from PIL
Merge pull request #162 from d-schmidt/master

added tests to cover save of four different png transparencies
fixed duplicate dpkg