This commit removes <, > and instead uses &lt;,&gt; to describe the
enter command in the boot command code block in vmware builder
documentation.

When verifying large files, the checksum would take a long time and
downloader would be nil. When the goroutine asked for progress,
it would raise a nil exception.

website: Fix typos in setup page

Fix typo in README.md

website: Fix typo in README.md

website: Fix typo in platform docs

website: Fix reference of typo corrected on 43bb20d

builder/amazonebs: Fix a typo.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>

website: typo: either rather than ether on why page

cc/ @mitchellh