Check local.properties
Export readLocalPropertiesValue
Use project.file method
Look up local.properties as default
Update README.md
s/readSdkDir/guessSdkDir/ and improve README
Merge pull request #1 from gfx/check_local_properties

s/readSdkDir/guessSdkDir/ and improve README
Merge pull request #1 from rejasupotaro/check_local_properties

Check local.properties