add rpath linker option in binding.gyp when --sqlite option is used

fixes #108

issue is that we perform auto-detection of the parameter style based on
the type of the first parameter. if it is an object, we switch to the
object syntax. however, buffers are also objects, so we have to special
case them too like RegExp and Date.

Conflicts:
	package.json

This reverts commit 2572bb86.

add script to build a cross walk from node semver to process.versions.modules value - refs https://github.com/developmentseed/node-sqlite3/wiki/Binaries

ensure we use integers for node abi version - in the case of node v0.11.3 this converts 0x000C -> 12

Support for binary deployment

default to installing from pre-built binaries: build from source now with 'npm install --build-from-source'

remove && in engins

added a section that explains rebuilding sqlite3 for node-webkit

Code improvements

Fix installation instructions in README.md