encoding issue in qio

[ChristinaXu2017]

Is your feature request related to a problem? Please describe.
Every implementation of the Java platform is required to support the following standard charsets: US-ASCII, ISO-8859-1, UTF-8/16/16BE/16LE. Every instance of the Java virtual machine has a default charset, java one-argument constructors of IO class, such as, FileReader, always use the platform default encoding which is generally a bad idea.

The qio is a collection of File reader/writer for our internal files, such as GFF, VCF, MAF etc. So far we used default encoding, but we should set it to UTF-8, due to these internal files including gzip files are pure English character, even the description in BAM file are UTF-8.

Describe the solution you'd like
All constructors in qio use default UTF-8 if it is single argument method; we also allow user to set charset by multi-argument constructors.