Add some ugly workarounds for segmentation faults on 32 bit architectures

These are caused by mozilla/rust#11040

Closes #86
Merge pull request #147 from bjz/ugly-fixes

Add some ugly workarounds for segmentation faults on 32 bit architectures
.travis.yml: Download rustc from rust-lang.org
Merge pull request #148 from ozkriff/master

.travis.yml: Download rustc from rust-lang.org
Use bitflags! to implement Modifiers
Merge pull request #149 from bjz/modifiers

Use bitflags! to implement Modifiers