2021.1029.0: Automatically build Mediapipe native libraries during `dotnet build` …

…(#58)

* Added PreBuildEvent to Linux runtime project

* Added PreBuildEvent to Windows runtime project

* Fix dumb Powershell error

* Remove quotes

* Test PowerShell before building

* Fix path

* Putting expression in quotes to see what happens

* Only test on Windows

* Temporarily not building on Windows

* Remove Test Powershell on CI

* Bring back quotesand print PSVersionTable

* Use Batch syntax instead of Powershell syntax

* Uncomment Windows .NET Build task on CI

Akihabra Debut 2

ci: pass tests on Windows (#49)

* build: copy opencv.BUILD from MediaPipeUnityPlugin

* chore: current end_of_line is LF

* build: remove opencv_deps option

* ci: enable Windows

* build: pass environment variables to build OpenCV

* ci: disable LAPACK

* ci: ignore SignalAbortTest on Windows

* test: fix tests on Windows

* doc: remove an incorrect line

* Do not upload contents of build/

We already have Bazel Caching so I doubt we even needed this.

Co-authored-by: Capuccino <ayane@vignetteapp.org>

Akihabara Debut 1

Fix remaining bugs of the library (#29)

* Starting to fix every literal bug of the lib

* Removed protofiles as they should be downloaded automatically through the build script

* Tried to reintegrate mediapipe_api, third_party and build.py... Still doesn't build

* Added another missing Assert()

* Added *another* other missing Assert()

* Remove CharSet attribute

The `CharSet = CharSet.Unicode` was making the test fail.

* Remove CharSet attribute on google logging unsafe native methods

* Mismatch: MpPtr

* D:

* Added StandardError enum

* Re-add opencv flags and disable Windows again

* Make SignalAbortAttribute filterable

Co-authored-by: Capuccino <chinodesuuu@gmail.com>