Directory layout

[eddieantonio]

Addresses #4. Requesting @amitdo for code review. If it looks good to you, I'll merge it and make it the v6.1 release.

[eddieantonio]

The structure now looks like this:

.
├── bin
│   └── [compiled binaries]
├── lib
│   └── libisri.a
├── libexec
│   └── [executables used internally] 
├── share
│   └── man
│       └── man1
│           └── [man pages for binaries]
├── src
│   └── [source files for library AND binaries]
├── test
│   └── [unit tests]
└── README.md

[amitdo]

Yes, it looks good to me. Thanks!