Added .gitignore
Added bower support, and support for loading as an AMD module

1. Added bower configuration
2. Moved source to src/ directory
3. Wireup so that when used as an AMD module, d3.layout.cloud mixes in with d3
4. Created AMD module example
Export cloud layout instead of d3
Merge branch 'amd'
Added pluggable random number generator
Merge branch 'pluggable-random'