Enrich ReducedToFalse prover/verifier error with pretty printed ErgoTree and evaluation environment

[greenhat]

Close #625

[coveralls]

Pull Request Test Coverage Report for Build 6480216007

• 42 of 99 (42.42%) changed or added relevant lines in 9 files are covered.
• 14 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.2%) to 80.768%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
ergo-lib/src/chain/transaction/reduced.rs	6	7	85.71%
ergo-lib/src/wallet.rs	0	1	0.0%
ergotree-interpreter/src/sigma_protocol/prover.rs	3	4	75.0%
ergotree-interpreter/src/eval.rs	20	23	86.96%
ergotree-interpreter/src/eval/error.rs	0	9	0.0%
ergotree-ir/src/mir/value.rs	3	45	6.67%

Files with Coverage Reduction	New Missed Lines	%
ergotree-interpreter/src/sigma_protocol/verifier.rs	1	90.0%
ergo-merkle-tree/src/merkletree.rs	2	97.39%
ergo-merkle-tree/src/batchmerkleproof.rs	3	90.48%
ergotree-ir/src/serialization/types.rs	8	81.18%

Totals
Change from base Build 6456988878:	-0.2%
Covered Lines:	10537
Relevant Lines:	13046

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💛 - Coveralls