tools: define size/cost of tool as regular properties of the tool

rather than using a giant switch block to determine size/cost

git-svn-id: http://micropolis.googlecode.com/svn/trunk@913 d9718cc8-9f43-0410-858b-315f434eb58c
tools: define default tool colors

so that colors do not need to be explicitly specified every time
a new tool is defined.

git-svn-id: http://micropolis.googlecode.com/svn/trunk@914 d9718cc8-9f43-0410-858b-315f434eb58c
tools: make translation strings optional for tools

If a translation string is not defined for the tool name, icon name,
or tool description, then an automatic string is generated.

git-svn-id: http://micropolis.googlecode.com/svn/trunk@915 d9718cc8-9f43-0410-858b-315f434eb58c