* Add ARMv7 as CI test target
* Avoid UB in conversions from floating point
When truncating floating point values to integer values, we need to
avoid undefined behavior if the argument does not fit into the target
type which is currently impossible using casts of primitive types.
Hence, this reimplements those conversions using arbitrary precision
integers and rationals from the num crate.
* 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