Add badges (#34)

* add badges

* add codecov

Author: yeesian

.travis.yml

@@ -15,4 +15,4 @@ script:
     - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi
     - julia -e 'Pkg.clone(pwd()); Pkg.build("LibGEOS"); Pkg.test("LibGEOS"; coverage=true)'
 after_success:
-    - julia -e 'cd(Pkg.dir("LibGEOS")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())';
+    - julia -e 'cd(Pkg.dir("LibGEOS")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder()); Codecov.submit(Codecov.process_folder())';

README.md

@@ -1,5 +1,8 @@
 LibGEOS.jl
 ==========
+[![Build Status](https://travis-ci.org/JuliaGeo/LibGEOS.jl.svg)](https://travis-ci.org/JuliaGeo/LibGEOS.jl)
+[![Build Status](https://ci.appveyor.com/api/projects/status/github/JuliaGeo/LibGEOS.jl?svg=true&branch=master)](https://ci.appveyor.com/project/JuliaGeo/LibGEOS-jl/branch/master)
+[![Coverage Status](https://coveralls.io/repos/github/JuliaGeo/LibGEOS.jl/badge.svg)](https://coveralls.io/github/JuliaGeo/LibGEOS.jl)
 
 LibGEOS is a LGPL-licensed package for manipulation and analysis of planar geometric objects, based on the libraries [GEOS](https://trac.osgeo.org/geos/) (the engine of PostGIS) and JTS (from which GEOS is ported).