* Improve lib template on Travis

This commit contains changes on the generated lib template to build
cross-platform libs. With this changes, I was able to setup a [Travis]
build with GitHub [Releases] of a cross-platform lib.

It is not possible yet to build a different crate type only using
command line args. It requires a modification on `Cargo.toml` to include
new types of library outputs. I've already opened an issue on [cargo](rust-lang/cargo#6160) to see what should be the case here.

Meanwhile, lib authors must change `Cargo.toml` and include the extra
`crate-type` attribute with all the libs. Sadly, this also means that
`LTO` optimisation is not available if the lib uses `lib` or `rlib`
attributes.

To avoid modifying the `Cargo.toml`, the sugestion would be that on a
future PR we could add to the deploy script a modification on the
`Cargo.toml` manifest to include the corresponding crate-type, and only
such crate type for that target. This means we would be able to bring
LTO and output smaller libs.

Realated to:
- #11

[Travis]: https://travis-ci.org/bltavares/rust-over-jna-example/builds/439439854
[Releases]: https://github.com/bltavares/rust-over-jna-example/releases/tag/initial

Signed-off-by: Bruno Tavares <connect+github@bltavares.com>

* Define the type of artifact to be produced by cargo.

s command `cargo` subcommand is exclusively intended to be used to help
with [working arround](rust-lang/rust#51009)
how crate types are defined, in order to help with cross-platform
builds.

It is currently [not possible](rust-lang/cargo#6160) to define a
single `crate-type` override on `cargo build`, which causes libs
intended to be used on other languages to compile more than one type of
crate.

This commit adds a dependency on this [new CLI app](https://github.com/bltavares/cargo-crate-type) to be able to workaround the limitations of Cargo.

We are now able to enable the `-C lto` optimization again, as we will
only compile a single type of artifact

Signed-off-by: Bruno Tavares <connect+github@bltavares.com>