0.5.0 release

[aldanor]

• The GitHub repository has been renamed to aldanor/hdf5-rust (need to double-check that travis/appveyor etc still work as intended)
• libhdf5-sys (libhdf5_sys) has been renamed to hdf5-sys (hdf5_sys)
• hdf5-rs (h5) has been renamed to hdf5
• Updated readmes, badges, etc
• Versions of all crates bumped to 0.3.0 (we initially planned to go with 0.3.0a but that would cause confusion since "0.3" is not <= than "0.3.0a", IIUC)
• Preparing all of this for release on crates.io

Closes #24.

[aldanor]

The story with the existing crates is this: because of naming collision with previous hdf5/hdf5-sys crates and because of renaming, (1) all versions of the current hdf5/hdf5-sys will be yanked from crates.io; (2) all pre-0.3 versions of hdf5-rs, libhdf5-sys, libhdf5-lib, remutex, hdf5-types will be yanked from crates.io when we release v0.4.

This way, this version (0.3) will be the only earliest one remaining, and all versions of all hdf5-* crates on crates.io will be fully working and stable.

Also (due to my initial misunderstanding of how cargo yank works), the version of this crate will have to be bumped to 0.5.0, so it doesn't overlap with previous hdf5/hdf5-sys version ranges.