* add default-enabled std feature
* use parity-wasm/std feature only if std is enabled
* drop dependency on std::io
* use hashmap_core instead of std::collections::HashMap
* disable std::error in no_std
* core and alloc all the things
* mention no_std in readme
* add no_std feature and use hashmap_core only on no_std
* rename the no_std feature to core
* drop dependency on byteorder/std
* simplify float impl macro
* remove some trailing whitespace
* use libm for float math in no_std
* add note about no_std panics of libm to readme
* Embed nan-preserving-float crate.
* Add no_std check to the Travis CI config
* add missing dev-dependency