Support standard log formats

[Sean Kauffman]

The format supported by default by nfer is not very standard and is what it is because it's the easiest thing to pull out of a Postgres database. While this format should be kept around, it would be smart to support other, more standard formats. When being addressed, this enhancement should really be broken up into several for specific log formats.

For example, we might choose to support the Apache log file format. We might also want to support the format used by Linux ftrace, or QNX tracelogger.