NoJira: Fix README syntax, and minor text changes

[kinow]

Thank you for contributing to Apache OpenNLP.

In order to streamline the review of the contribution we ask you
to ensure the following steps have been taken:

For all changes:

• Is there a JIRA ticket associated with this PR? Is it referenced
  in the commit message?

• Does your PR title start with OPENNLP-XXXX where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character.

• [ X ] Has your PR been rebased against the latest commit within the target branch (typically master)?

• [ X ] Is your initial contribution a single, squashed commit?

For code changes:

• Have you ensured that the full suite of tests is executed via mvn clean install at the root opennlp folder?
• Have you written or updated unit tests to verify your changes?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE file, including the main LICENSE file in opennlp folder?
• If applicable, have you updated the NOTICE file, including the main NOTICE file found in opennlp folder?

For documentation related changes:

• [ X ] Have you ensured that format looks appropriate for the output in which it is rendered?

Note:

Please ensure that once the PR is submitted, you check travis-ci for build issues and submit an update to your PR as soon as possible.

[kinow]

It is not well documented in GitHub flavoured Markdown docs, but they changed it some months ago, and unless you add a new line after the title, it is not displayed as a heading.

This pull request includes a blank line after a heading.

It also fix possible typos (a review of an English speaker would be good).

Cheers
Bruno

[kinow]

To preview changes: https://github.com/kinow/opennlp/tree/update-project-readme

[coveralls]

Coverage remained the same at 57.144% when pulling 95e43b3 on kinow:update-project-readme into 99cbf0d on apache:master.

[smarthi]

+1 merge this please