tomcat: add options for SSL, APR, gzip and docs

- Added option to configure tomcat for SSL (https support) using self signed certs. If building with APR, generate a cert using OpenSSL, otherwise generate a cert using java's keytool.
- Added option to set up Apache Portable Runtime (depends on tomcat-native)
- Added option to configure gzip compression when serving compressable mime types
- Added option to download and install tomcat docs locally for offline reference. Get tomcat 8 docs if --devel is specified
- Verified all above functionality on tomcat 8 (when --devel is specified)