integrate 'koch web' features into koch; deprecate 'nimweb' tool

doc/tools.rst

@@ -0,0 +1,20 @@
+========================
+Tools available with Nim
+========================
+
+The standard distribution ships with the following tools:
+
+- | `Documentation generator <docgen.html>`_
+  | The builtin document generator ``nim doc`` generates HTML documentation
+    from ``.nim`` source files.
+
+- | `Nimsuggest for IDE support <nimsuggest.html>`_
+  | Through the ``nimsuggest`` tool, any IDE can query a ``.nim`` source file
+    and obtain useful information like definition of symbols or suggestions for
+    completion.
+
+- | `C2nim <c2nim.html>`_
+  | C to Nim source converter. Translates C header files to Nim.
+
+- | `nimgrep <nimgrep.html>`_
+  | Nim search and replace utility.