Providing a way to eliminate extra dependencies

[djc]

I just upgraded from chrono_tz 0.5.3 to 0.6.0 and in the process, a whole bunch of new dependencies appeared in my Cargo.lock: chrono-tz-build, phf, phf_codegen, phf_codegen, phf_generator, phf_shared, siphasher and uncased. These seem to be required in 0.6.0 even if I disable the default features. #84 seems to have introduced most of these.

Please consider restructuring things so that this stuff can be disabled. My project really only wants chrono_tz::America::Los_Angeles, and it would be a pity if pulling in all this other stuff was mandatory.

[frederikhors]

@djc did you find a way?

[djc]

I did not.