1.7.0

This release of string_view lite contains the following additions, fixes and changes.

Additions:

• Add prevention to construct, convert from nullptr, p2166 (#47, thanks @mbs-c).
• Add configuration option nssv_CONFIG_NO_STREAM_INSERTION to omit streams (#42, thanks @theShmoo).
• Add export() to CMakeLists.txt, enabling importing targets, nonstd-lite-project issues 50.
• Add script tc-cl.bat, nonstd-lite-project issues 54.
• Add GitHub Actions CI.

Fixes:

• Fix prevention to construct, convert from nullptr for presence of =delete, p2166 (#47).
• Fix check for stream to use sentry (#46, thanks mprather).
• Fix parameter type from char to CharT for older compilers (#45, thanks @Elite-stay).
• Fix link to LLVM libc++ implementation of string_view (thanks @striezel, #44).
• Fix typos in string_view.hpp (thanks @striezel, #43).
• Fix identical mangled names for clang on Windows (#40, thanks @nickhutchinson).

Changes:

• Make find() constexpr in C++11 (#48, #49, thanks @eyalroz).
• Get rid of non-constexpr std::swap() (#41, thanks @stdbug).
• Replace _CPPUNWIND with _HAS_EXCEPTIONS (thanks @DBJDBJ, nonstd-lite-project issue 49).
• Change value used with *_CPP20_OR_GREATER to 202002L (nonstd-lite-project issue 60).
• Update actions/checkout in GitHub Actions to v3 (#51, nonstd-lite-project issue 63).
• Add msvc (windows-2022) image to GitHub Actions, nonstd-lite-project issue 62.
• Remove msvc (windows-2016) image from GitHub Actions (thanks @xavier2k6, nonstd-lite-project issue 61).
• Handle lest test framework as system include to prevent warnings.