ConTeXt and LaTeX templates: more cleanup (Andrew Dunning).

- Formatting of some conditionals is adjusted to provide cleaner spacing and
  punctuation in generated preamble.

- `$for$` is always provided where the user might want to use multiple options
  (does not change existing functionality).

- `hyperref` link rendering revised per discussion in
  a84f822c30:

    - the `hidelinks` option is now effectively the default (and has
      been removed as a separate option), rather than setting all links to
      black;
    - link colours can be enabled more easily (using a slightly darker version
      of the old Pandoc defaults) using a new `colorlinks` variable;
    - `pdfborder={0 0 0}` is automatically enabled in `hyperref` when
      `colorlinks` is enabled, and is now only applied.

- ConTeXt only:
    - microtype applied to both regular text and small caps;
    - `indenting` variable added;
    - renamed `style` to `linkstyle` for consistency (had not yet made it
      into the README through my oversight, which I will correct);
    - separated `linkcontrastcolor` from `linkcolor`;
    - matching LaTeX `hyperref` usage, only disable link styling rather
      than providing a specific setting.

data/templates

@@ -1 +1 @@
-Subproject commit 12a0110a0a5baeb56436275006dbda7ce119e3d3
+Subproject commit ef963c30605d7f0558b9cfbf7183f0aa4aad688e