THRIFT-4350: enable dotnet-2.0.0-sdk in ubuntu xenial, update netcore
projects, get them running with make cross
Client: netcore

This closes #1379
diff --git a/.gitignore b/.gitignore
index 3fd7826..faa1a5b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -327,6 +327,7 @@
 /test/netcore/**/obj
 /test/netcore/**/gen-*
 /test/netcore/Thrift
+/test/php/php_ext_dir/
 /test/rs/Cargo.lock
 /test/rs/src/thrift_test.rs
 /test/rs/bin/