Move minimal Django version to 1.5

There are too big differences between 1.4 and 1.6 to maintain full
compatibility with both of them.

.travis.yml

@@ -3,11 +3,10 @@ python:
   - "2.7"
 env:
   matrix:
-    - DJANGO_VERSION=1.4.10 TRAVIS_DATABASE=sqlite
-    - DJANGO_VERSION=1.6 TRAVIS_DATABASE=sqlite
     - DJANGO_VERSION=1.5.5 TRAVIS_DATABASE=mysql
     - DJANGO_VERSION=1.5.5 TRAVIS_DATABASE=postgresql
     - DJANGO_VERSION=1.5.5 TRAVIS_DATABASE=sqlite
+    - DJANGO_VERSION=1.6 TRAVIS_DATABASE=sqlite
   global:
 # Sauce labs setup
     - secure: "W4EtqCQSbSWb2sDwHd0obttzUTKIPyFZE90qD+YdV76YLgIK7QX4Vc6Hx9fRRNy397h4RrYIzyU2vemGIR5j8cR16Y6MyJ8Fy4DyC2mHyo3T7Tx4/cJYTQDPF2G4kxjR+vmhsdQIdmaYLsjtb2C2M0aIkU8FGFv6D3+TXqsoOmI="

docs/admin/install.rst

@@ -10,7 +10,7 @@ Requirements
 
 Python (2.7)
     http://www.python.org/
-Django (>= 1.4)
+Django (>= 1.5)
     https://www.djangoproject.com/
 Translate-toolkit (>= 1.9.0, 1.10.0 or newer strongly recommended)
     http://toolkit.translatehouse.org/

docs/changes.rst

@@ -7,6 +7,7 @@ weblate 1.9
 Released on ? 2013.
 
 * Django 1.6 compatibility.
+* No longer maintained compatibility with Django 1.4.
 
 weblate 1.8
 -----------

requirements.txt

-Django>=1.4
+Django>=1.5
 GitPython>=0.3.2.RC1
 South>=0.7
-Whoosh>=2.5
+Whoosh>=2.5.2
 Translate-Toolkit>=1.10.0
 lxml>=3.1.0
 Pillow

trans/requirements.py

@@ -89,7 +89,7 @@ def get_versions():
         name,
         url,
         mod.get_version(),
-        '1.4',
+        '1.5',
     ))
 
     name = 'python-social-auth'

weblate.spec

@@ -12,11 +12,11 @@ BuildRequires:  graphviz-gd
 Url:            http://weblate.org/
 Requires:       apache2-mod_wsgi
 Requires:       cron
-Requires:       python-django >= 1.4
+Requires:       python-django >= 1.5
 Requires:       python-social-auth >= 0.1
 Requires:       translate-toolkit >= 1.10.0
-Requires:       python-GitPython >= 0.3
-Requires:       python-whoosh >= 2.5
+Requires:       python-GitPython >= 0.3.2
+Requires:       python-whoosh >= 2.5.2
 Requires:       python-imaging
 Requires:       python-South >= 0.7
 %py_requires