add gitignore file to avoid checking in Build environment (and others)

.gitignore

+# Compiled source #
+###################
+*.bin
+*.com
+*.class
+*.dll
+*.exe
+*.o
+*.so
+*.pyc
+__pycache__
+
+# Packages #
+############
+# it's better to unpack these files and commit the raw source
+# git has its own built in compression methods
+*.7z
+*.dmg
+*.gz
+*.iso
+*.jar
+*.rar
+*.tar
+*.zip
+*.tar.gz
+*.tgz
+
+# Logs and databases #
+######################
+*.log
+*.sql
+*.sqlite
+
+# OS generated files #
+######################
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Linux packages #
+##################
+*.deb
+*.rpm
+
+# Build environments #
+######################
+
+build/
+
+# Vim #
+#######
+
+# swap
+[._]*.s[a-v][a-z]
+[._]*.sw[a-p]
+[._]s[a-v][a-z]
+[._]sw[a-p]
+ # session
+Session.vim
+# temporary
+.netrwhist
+# auto-generated tag files
+tags