FIXES: #2527
* define custom docker image for travis-linux builds based on
package build image
* add macos builds
* add windows builds (currently allowed to fail)
* improve build and shell scripts as required for the CI envs
* add asio timer latency workaround
* omit several manual tests from TravisCI which cause memory exhaustion
Fixes: RIPD-1648
- use ExternalProject for snappy, lz4, SOCI, and sqlite3
- use FetchContent for NuDB
- update SOCI from 79e222e3c2278e6108137a2d26d3689418b37544 to
3a1f602b3021b925d38828e3ff95f9e7f8887ff7
- update lz4 from c10863b98e1503af90616ae99725ecd120265dfb to v1.8.2
- update sqlite3 from 3.21 to 3.24
- update snappy from b02bfa754ebf27921d8da3bd2517eab445b84ff9 to 1.1.7
- update NuDB from 00adc6a4f16679a376f40c967f77dfa544c179c1 to 1.0.0