Set up .gitignore

this is a library, and so we shouldn't keep Cargo.lock

we never want to keep target
fix time deprecation

by using the external crate rather than the intenral one
Remove unneeded Cargo.toml lines

These are already the defaults, no need to specify.
Fix unused import warning
remove immutibility warning
remove if-let warning
add a basic README
Merge pull request #1 from steveklabnik/master

Some fixes