Meta-manipulation separated from compilation.

There were `Compiler >> setupClass:`
and `ClassBuilder >> setupClass:`. They did the same.
Now, `ClassBuilder` one is used exclusively.

In `install:forClass:category:`, the "set up a compiled method"
was extracted into `ClassBuilder` and was reused from other places.

Now, if you have `CompiledMethod`, you can install it without
dependency on `Compiler`.
BlockClosure >> asCompiledMethod

Allows creating CompiledMethod from a block.
Combined with previous commit's `ClassBuilder >> install:...`
it allows to add dynamic api in runtime using parametrized
block, without needing the `Compiler` to actually compile
Smalltalk source.

(in deployed scenario, there is no Compiler,
but there is a need to "compile" various kind of templates)
Merge pull request #346 from herby/meta-compile-separation

Meta compile separation
More improvements to the debugger
- Renamed ClassBuilder >> installCompiled:forClass:category: to #installMethod:forClass:category
- Changed public ClassBuilder method protocol to 'api'
BlockClosure >> currySelf

Transform plain [ :x :y ... ] block that is to be called
as f(x,y,...) in JS into function that can be used as a JS method,
that it, should be called as x.f(y,...).

Usable with asCompiledMethod.
Merge pull request #348 from herby/curry-self

BlockClosure >> currySelf
Fix issue #349
BlockClosure >> currySelf reformatting
Adding "declarative custom tags" into HTMLCanvas.

This adds `HTMLSnippet` class which collects all
```
<tag html-snippet="quux">
  ...
  <innertag html-snippet="*" />
  ...
</tag>
```
structures in the page and detaches them. Then it allows to use
```
  html quux with: [ html p with: 'Text' ]
```
to render
```
<tag>
  ...
  <innertag><p>Text</p></innertag>
  ...
</tag>
```
in the page.
Thus, you can define pieces of page structure declaratively
in html and use whole snippets as selector in HTMLCanvas.
The tag with `html-snippet="*"` becomes the "caret", that is,
it is simulated as if it was just added and you can continue
with `with:`, `at:put:` etc.
Removed doesNotUndestand:, installing snippets directly.
HtmlSnippet >> initialize to set up snippets automatically
Canvas-Snippet: Moved to Canvas package.
Made refactorings as required.

  - Add a class comment on HTMLSnippet
  - Rename HTMLCanvas >> snip: to #snippet:
  - Cleanup HTMLSnippet class-side initialization (extract current initialization into an instance-side method maybe?)
  - Exctract lazy initialization of 'snippet' inst var to an accessing method
Merge pull request #347 from herby/snippet

Adding "declarative custom tags" into HTMLCanvas.
HTML Snippets refactorings
Renamed HtmlSnippet to HTMLSnippet
Refactoring anAssociation out.
Merge pull request #351 from herby/snippets-fixes

Refactoring anAssociation out.
Fix the remains of old name HtmlSnippet.

Renaming was wrong, probably.