* fixed presentation of flow mappings inside block collections
* improved logic checking whether a collection can be written on a
single line
* fixed tests
* added yaml/style that defines representation pragmas
`scalar` and `collection`
* implemented those pragmas
* updated docs. also fixes some invalid links in docs
* dumping doesn't work at CT
* timestamps don't work at CT
* aliases don't work at CT
* renamed tserialization -> tnative to mirror rename of native.nim file
* added comptime tests to tnative, currently only execute when doing
nim nativeTests, because of compiler bug
* Fixes#70, #91
