SCHEMA-538.  Corrected KijiNotInstalledException error msgs

SCHEMA-538.  Corrected KijiNotInstalledException

New constructor uses reference to KijiURI instead of a String
representing only the instance name.

Retained legacy constructor and getInstanceName() method, but added new
constructor and getURI() method.

SCHEMA-538.  Corrected KijiNotInstalledException

Exception constructor was given full URI for uninstalled instance
instead of just the instance name.

KijiNotInstalledException stores full URI string

Previously, it contained a string containing only the name of the
uninstalled component, and whomever caught the exception had to add
"kiji://.env/" to the beginning of the error message.

KijiNotInstalledException retains legacy constructor

Updated KijiNotInstalledException such that the old constructor (which
took just an instance name as an argument) is still present, but marked
as @deprecated.

Replaced "String getURIName" with "KijiURI getURI"

Other minor changes based on feedback from Christophe (used
Preconditions instead of regular assert, fixed some javadoc formatting)

SCHEMA-538.  Javadoc and final cleanup.