FIX - gzip all text XML / JSON / TEXT contents from petascope to clients

[Bang Pham Huu]

Petascope can be enhanced to gzip all text contents when:

• A client sends a HTTP header contains this message

   Accept-Encoding: gzip
  

• Then, it will compress text from response by Java code (no Tomcat configuration here) and attach this header:

   Content-Encoding: gzip
  

• Web browser will automatically extract the content from it.

This is backward-compatibility, for example, older petascope (or plain client like curl) will just see the raw text as it is.