build system insufficient for installers

[Sam Hartman]

The build system doesn't produce all the artifacts that an installer needs. In particular, it does not:

* install the shared library

* build chrome/chromium and firefox extensions.

I expect that when cmake . is run in the source tree, and the cmake cache edited to set the right installation prefix and destdir that

make all
make install
will result in

* the executable being placed in the bin directory of the install prefix
* the shared library being placed in the lib directory
* the browser extensions being placed under some path in the install prefix.

[Margaret Cullen (mrw42)]

This should be dealt with when/if we develop installers.