[FIX] P3: metadata update

* gitignore pycache folders (apparently appear for some)
* update xlwt requirement: 1.1.2 does not work with Python 3.6, 1.2 should work, 1.3 officially supports it

.gitignore

@@ -7,6 +7,7 @@ _build/
 !.mailmap
 # compiled python files
 *.py[co]
+__pycache__/
 # setup.py egg_info
 *.egg-info
 # emacs backup files

requirements.txt

@@ -37,5 +37,5 @@ vatnumber==1.2
 vobject==0.9.3
 Werkzeug==0.11.11
 XlsxWriter==0.9.3
-xlwt==1.1.2
+xlwt==1.3.*
 xlrd==1.0.0