Merge #583: Clean up miniscript/mod.rs

a60c642 Refactor satisfy* functions (Tobin C. Harding)
e1e95d3 Compress patter match in script_size (Tobin C. Harding)
23897d1 Put the two Miniscript impl blocks together (Tobin C. Harding)
5fd22a6 Move Miniscript satisfy* functions into main block (Tobin C. Harding)
32342de Move Miniscript max_satisfaction* to main block (Tobin C. Harding)
e3c1b7c Move Miniscript encode/script_size into main block (Tobin C. Harding)
dbf9a62 Combine Miniscript conversion and constructor blocks (Tobin C. Harding)
6c5db91 Move Miniscript impl block under type (Tobin C. Harding)
fd09756 Make Miniscript cmp/ord/hash docs uniform (Tobin C. Harding)
1d1ac37 Move Miniscript Hash impl underneath others (Tobin C. Harding)
ccb05b5 Improve rustdocs on Miniscript type (Tobin C. Harding)

Pull request description:

  Make an effort to clean up the `miniscript/mod.rs` file. I could not see a reason for all the separate impl blocks, is there one? Please note this PR does not fix all the docs, just does ones that should not be too hard to review.

ACKs for top commit:
  apoelstra:
    ACK a60c642

Tree-SHA512: 2fb555f5f399fd037b177c6d2e1224915d303c6bc13de8eb2d51143e48caf7a61e6bdd8bf0cbdac7fb95a29c00ef13bf8fe0aac1a3b9d9ca47ce59e63ced041e

Author: apoelstra