create one-based tabix index files by default
create one-based tabix index files by default

- previously index was 0-based, regardless of user specification


git-svn-id: d94a30e01ab1b9ad8a77470aceaf61700f3c3450@61378 bc3139a8-67e5-0310-9ffc-ced21a209358

nhayden/Rsamtools,jimhester/Rsamtools,jimhester/Rsamtools,mtmorgan/Rsamtools,nhayden/Rsamtools,mtmorgan/Rsamtools,nhayden/Rsamtools,jimhester/Rsamtools,jimhester/Rsamtools,mtmorgan/Rsamtools,mtmorgan/Rsamtools,nhayden/Rsamtools