Build product

Don't use org.eclipse.core.runtime.products extension point as it
duplicates .product file.

Relocate icons and splash to the same directory as a product file and
reference them using relative path.

Drop custom config.ini file: it will be generated based on the .product
file.

Start org.eclipse.core.runtime bundle automatically.

All packaging is done by Tycho itself which makes package.sh script
obsolete.
Extract LICENSE.txt, NOTICE.txt and README.txt from org.neo4j.neoclipse bundle

- during package phase, materialize products with
  tycho-p2-director-plugin's materialize-products goal;
- during package phase, unpack required files from just built
  org.neo4j.neoclipse bundle using Ant's unzip task;
- during pre-integration-test phase (instead of package phase, which is
  default), assemble final archives with tycho-p2-director-plugin's
  archive-products goal.
Place LICENSE.txt, NOTICE.txt and README.txt into every product

Materialized products follow such folder structure:

    > tree -d -L 4 repository/target/products/neoclipse/
    repository/target/products/neoclipse/
    |-- macosx
    |   |-- carbon
    |   |   `-- x86
    |   |       `-- neoclipse-1.9.1-SNAPSHOT
    |   `-- cocoa
    |       |-- x86
    |       |   `-- neoclipse-1.9.1-SNAPSHOT
    |       `-- x86_64
    |           `-- neoclipse-1.9.1-SNAPSHOT
    `-- win32
        `-- win32
            |-- x86
            |   `-- neoclipse-1.9.1-SNAPSHOT
            `-- x86_64
                `-- neoclipse-1.9.1-SNAPSHOT

Place extracted files into every product's root directory with a copy
target (unzip target has no support for multiple mappers).

As there is no way to tell a mapper to place a file into every directory
4 levels deep, we have to enumerate all of them explicitly. To find all
such target directories, run:

    > find repository/target/products/neoclipse/ -mindepth 3 -maxdepth 3 -type d
    repository/target/products/neoclipse/hpux/gtk/ia64_32
    repository/target/products/neoclipse/linux/gtk/x86
    repository/target/products/neoclipse/linux/gtk/ppc64
    repository/target/products/neoclipse/linux/gtk/x86_64
    repository/target/products/neoclipse/win32/win32/x86
    repository/target/products/neoclipse/win32/win32/x86_64
    repository/target/products/neoclipse/macosx/cocoa/x86
    repository/target/products/neoclipse/macosx/cocoa/x86_64
    repository/target/products/neoclipse/macosx/carbon/x86

[1] Mapping File Names, https://ant.apache.org/manual/Types/mapper.html