Julia 1.0+ compatibility; add Project Toml; adapt travis for codecoverage

[hhaensel]

Some people, including myself, are missing the functionality of StringLiterals in the latest Julia version. So I thought, why not making this nice package 1.0 compatible.

The changes are

• added the compatibility functions start(), next() and done() for iterables which were removed from Julia 1.0 on
• created a Project.toml and give the packge the version number 1.0.0-DEV
• adapted Travis to test with the inline=no option in order to get around the missing lines issue in Coverage.jl.

This version runs on all OSes with Julia versions from 0.6 to nightly. I hope, this could be a version to be again registered with the Julia repositories.

[coveralls]

Coverage decreased (-0.04%) to 99.453% when pulling 71f7d11eeba7795707f00748bad5e631f9344613 on hhaensel:hh/noinline into b96e0b013bd82aeeb8ad902aa40502ba8d4dd596 on JuliaString:master.

[ScottPJones]

OK, I'd been keeping StringLiterals around just for 0.x, because it has been superseded by using Strs, which uses StrLiterals and StrFormat. I'd prefer it if people move to that for any released Julia version, I don't intend to be doing further work (except possibly merging PRs) on StringLiterals.