removed unnecessary type conversion

Signed-off-by: Arvind Chembarpu <achembarpu@gmail.com>
rewrote primes_list with major tweaks
shows 30% performance improvement

Signed-off-by: Arvind Chembarpu <achembarpu@gmail.com>
ignore code testing files

Signed-off-by: Arvind Chembarpu <achembarpu@gmail.com>
fixed minor bounds error

Signed-off-by: Arvind Chembarpu <achembarpu@gmail.com>
updated timings

Signed-off-by: Arvind Chembarpu <achembarpu@gmail.com>