Merge pull request #1524 from hcollet/stata

First .gitignore for Stata files

Global/Stata.gitignore

+# .gitignore file for git projects containing Stata files
+# Commercial statistical software: http://www.stata.com
+
+# Stata dataset and output files
+*.dta
+*.gph
+*.log
+*.smcl
+*.stpr
+*.stsem
+
+# Graphic export files from Stata
+# Stata command graph export: http://www.stata.com/manuals14/g-2graphexport.pdf
+#
+# You may add graphic export files to your .gitignore. However you should be
+# aware that this will exclude all image files from this main directory
+# and subdirectories.
+# *.ps
+# *.eps
+# *.wmf
+# *.emf
+# *.pdf
+# *.png
+# *.tif