Add Mono.Options and Mono.Terminal to the tree.

They can be updated with the new `update-deps` target.

This is mainly to avoid complication with `pkg-config` on
OS X where we'd have to find and use the one included in
the Mono framework.
Bump nrefactory and debugger-libs.
Fix a typo in README.md.
Bump debugger-libs and nrefactory.
Update copyright notices to 2014.
Bump dependencies.
Bump debugger-libs and nrefactory.
Show disassembly in stack frames when source code is unavailable.

Also add a `PreferDisassembly` configuration option which tells
SDB to always use disassembly instead of trying to read source
code.

Fixes #14.
Minor adjustment to last commit.
Update debugger-libs.
Add a `jump` command.

This is like `jump` in GDB or 'Set Next Statement' in IDEs.

Fixes #13.
Add line numbers to `src`.

Fixes #16.
Some cosmetics in src/Commands/StepCommand.cs.
Don't print IL offsets when stringizing stack frames without source.

The offset is already present in the stack frame header.
Make configuration extensible.

Plugins can now declare configuration elements that they need. Those
will be saved/loaded as with other configuration elements, and can
be modified/viewed with the `cfg` command.

Fixes #2.
Sort the environment variable table.
Correctly set next watch/breakpoint IDs when restoring the debugger state from disk.
Ensure breakpoints are cleared before adding breakpoints read from a database file.
Add an `alias` command for defining simple aliases.

Fixes #11 (mostly).
Add a `DefaultDatabaseFile` configuration element.

One could, for example, set this to `/home/foo/.sdb.db` to have
SDB save the debugger database there by default without having
to specify the file name whenever the `db` command is invoked.