Fix transaction batch_execute
Reorder transaction methods
Bump rust-phf
Remove UUID support

The UUID crate is being split out from the standard Rust distribution,
and it doesn't make sense to force downstream code to pull that crate in
as well.
Remove old build system

Cargo is able to do everything we need and the last bit (doc tests)
should be merging soon.
Move travis to .travis
Remove remaining references to UUID
Remove some indirection from files
Fix doc build
Ignore cargo lockfile
Deprecate connection pool
Bump rust-phf
Fix pool documentation