HeadOf and TailOf

See #185, release log:

• 3776b5c by @rultor: Merge branch '__rultor'
• 145df21 by @rultor: Merge branch '__rultor'
• 9acf9a9 by @rultor: Merge branch '__rultor'
• 859cecb by @rultor: Merge branch '__rultor'
• ff1c9ed: #185 since tag fixed
• 107803f: #308 updated since tag
• ce82074 by @rultor: Merge branch '__rultor'
• e98ec3a: #308 bug fixed
• a93160d by @paulodamaso: Changes suggested in PR #819.
• 7a4e6a5: #308 removed static method
• 94a6173 by @paulodamaso: Resolving #766 - IoCheckedScal...
• 3e7881f: #308 modified algorithm
• 569b88d by @proshin-roman: #759: Implement ScalarWithFall...
• c7bf527 by @proshin-roman: #759: Implement ScalarWithFall...
• ed0b2a9 by @proshin-roman: Merge branch 'master' of https...
• 36c69b4: #185 conflicts resolved
• b7be7be: #185 review remarks
• 1ec6627 by @proshin-roman: #764: Implement HeadInput - fi...
• fa73936 by @proshin-roman: #764: Implement HeadInput - fi...
• ced96f1 by @rultor: Merge branch '__rultor'
• and 49 more...

Released by Rultor 1.67.2, see build log