add coveralls badge to show coverage number

.luacov

@@ -18,7 +18,7 @@ return {
   runreport = true,
 
   -- Delete stats file after reporting?
-  deletestats = true,
+  deletestats = false,
 
   -- Patterns for files to include when reporting
   -- all will be included if nothing is listed

.travis.yml

@@ -17,9 +17,13 @@ install:
     - git clone https://github.com/Olivine-Labs/busted/
     - cd busted && git checkout v1.10.0 && sudo luarocks make && cd ..
     - sudo luarocks install luacov
+    - sudo luarocks install luacov-coveralls --server=http://rocks.moonscript.org/dev
 
 script:
     - make fetchthirdparty all
     - sudo cp base/build/*/luajit /usr/bin/
     - make testfront
     - make coverage
+
+after_success:
+    - cd koreader-*/koreader && luacov-coveralls -v

README.md

@@ -1,4 +1,6 @@
-KOReader [![Build Status][travis-icon]][travis-link]
+KOReader
+[![Build Status][travis-icon]][travis-link]
+[![Coverage Status][coverage-icon]][coverage-link]
 ========
 
 KOReader is a document viewer application, originally created for Kindle 
@@ -189,4 +191,5 @@ http://ccache.samba.org
 [linux-vm]:http://www.howtogeek.com/howto/11287/how-to-run-ubuntu-in-windows-7-with-vmware-player/
 [l10n-readme]:https://github.com/koreader/koreader/blob/master/l10n/README.md
 [koreader-transifex]:https://www.transifex.com/projects/p/koreader/
-
+[coverage-icon]:https://coveralls.io/repos/koreader/koreader/badge.png
+[coverage-link]:https://coveralls.io/r/koreader/koreader