Update readme with information to clarify scons/cmake building, and list Grammatech's contributions.

Resolve "doesn't build on apple/mac"

Closes #19

See merge request !12

Resolve "No testing on ubuntu 20"

Closes #20

See merge request !13

Windows missing big-endian/little-endian conversion routines (e.g. be16toh)

See merge request !11

Antonio Flores Montoya authored 4 years ago and Jason Hiser committed 4 years ago

Added #define to use Window's builtin routines for conversion routines.
Explicit casting via static_cast to/from types was needed for c++11 compliant compilation
as an appropriate constexpr for size selection (e.g. be16toh vs. be32toh) is not
available until C++11.

Todo:  support compilation C++14,C++17, C++20.

Resolve "Turbo found 3 bugs in libEHP on Thu Apr 16 05:37:21 UTC 2020"

Closes #16

See merge request !10

If fde length reports longer than the section length, we need to abort parsing as the input is invalid.

Fix msvc warnings

See merge request !9

Fix warnings on MSVC

fix DW_EH_PE_omit case

See merge request !8

DW_EH_PE_omit is FF so it cannot be a case
of encoding_lower8. Instead it can be a check against
the complete encoding.

Update with new headers

See merge request !7