Fix #205 erlydtl warnings

By default, rebar are using {compiler_options, [return]} for erlydtl_opts which will fail the compilation if erlydtl reports any warning.

instead, use `[verbose, report_errors]` which is the default `compiler_options` in erlydtl.

In erlydtl 0.7.0, see https://github.com/erlydtl/erlydtl/blob/0.7.0/src/erlydtl_compiler.erl#L54
In erlydtl 0.8.0, see https://github.com/erlydtl/erlydtl/blob/0.8.0/include/erlydtl_ext.hrl#L17