Fix #920: Correct return-type lifting for exported methods
Implement StringBuilder.append(char[], ...) methods
Add toURI method to VirtualFiles
Fix #919: Remove local keys in sbt, since they make `inspect` fail
Fix #918: Implement identifier related methods on java.lang.Character
Fix #930: Propagate cause in IOException ctor chain
Improve error messages of DataInputStream (when reading UTF8)
Fix #933: Correct offset handling in ArrayBufferInputStream
Fix #935: DataInputStream for partially used ArrayBufferInputStreams

The special casing of DataInputStream for ArrayBufferInputStreams
behaved incorrectly, when the underlying stream was partially
consumed. This commit fixes this by exposing the
ArrayBufferInputStream's current position and using it instead of a
position variable internal to DataInputStream.
Improve exception information when deserializing IR
Merge pull request #921 from gzm0/fix-export-type-lifting

Fix #920: Correct return-type lifting for exported methods
Merge pull request #922 from gzm0/improve-string-builder

Implement StringBuilder.append(char[], ...) methods
Merge pull request #923 from gzm0/virtualfile-uri

Add toURI method to VirtualFiles
Merge pull request #936 from gzm0/deserialize-fail-info

Improve exception information when deserializing IR
Merge pull request #934 from gzm0/array-buffer-input-offset

Fix #933: Correct offset handling in ArrayBufferInputStream
Merge pull request #932 from gzm0/data-input-err-msg

Improve error messages of DataInputStream (when reading UTF8)
Merge pull request #931 from gzm0/io-exception-ctor

Fix #930: Propagate cause in IOException ctor chain
Merge pull request #929 from gzm0/unicode-idents

Fix #918: Implement identifier related methods on java.lang.Character
Merge pull request #926 from gzm0/fix-inspect

Fix #919: Remove local keys in sbt, since they make `inspect` fail
p Implement essential java.io.Readers