Added `with_bytes` and `with_mut_bytes`

Closes https://github.com/PistonDevelopers/image/issues/110
Use `rawbuf` and `mut_rawbuf` instead
Merge pull request #111 from bvssvni/master

Added `with_bytes` and `with_mut_bytes`
update to latest Rust
add num dependency
Merge pull request #115 from nwin/master

update to latest Rust
Add initial TIFF support. The abilities are quire rudimentary. So far only uncompressed grayscale images work.
Merge pull request #116 from nwin/master

Add initial TIFF support.
Removed debug print statements
Merge pull request #117 from nwin/master

Removed debug print statements
Replace failure with an error.
Added convenience function to save a buffer

Make it more convenient to write a buffer to a file.
Open the file write-only.
fixed formatting
Merge commit '2184609a44f38b659aa65dafe690ed380c20f538'
Merge pull request #118 from nwin/master

Added convenience function to save a buffer
Prepare release of 0.1
Revert "Prepare release of 0.1"

This reverts commit ee0704a4f124de72153aa30c52fc09471ac45f7e.
Prepare release of 0.1
Merge pull request #119 from nwin/master

Prepare release of 0.1