Added .gitignore file

Author: Alexander Konovalov

.gitignore

@@ -0,0 +1,20 @@
+doc/*.aux
+doc/*.bbl
+doc/*.bib
+doc/*.blg
+doc/*.brf
+doc/*.css
+doc/*.html
+doc/*.idx
+doc/*.ilg
+doc/*.ind
+doc/*.js
+doc/*.lab
+doc/*.log
+doc/*.out
+doc/*.pdf
+doc/*.pnr
+doc/*.six
+doc/*.tex
+doc/*.toc
+doc/*.txt