Fix directory name escaping

[RReverser]

Fixes various issues related to directory name escaping.

Before:

├── g.r{ou
│   └── p
│       ├── report
│       └── t{e.s
│           └── t
│               └── report
├── g_r{ou_p
│   └── t{e_s_t
│       ├── _a_b_
│       │   ├── base
│       │   ├── new
│       │   └── report
│       └── _c{d_
│           ├── base
│           ├── new
│           └── report
└── report

After:

├── g.r{ou_p
│   ├── report
│   └── t{e.s_t
│       ├── _a_b_
│       │   ├── base
│       │   ├── new
│       │   └── report
│       ├── _c{d_
│       │   ├── base
│       │   ├── new
│       │   └── report
│       └── report
└── report

Fixes #189.

[coveralls]

Pull Request Test Coverage Report for Build 438

• 0 of 22 (0.0%) changed or added relevant lines in 3 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.008%) to 13.004%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/report.rs	0	1	0.0%
tests/criterion_tests.rs	0	2	0.0%
src/html/mod.rs	0	19	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/html/mod.rs	1	1.32%
src/plot/summary.rs	1	0.0%

Totals
Change from base Build 433:	-0.008%
Covered Lines:	445
Relevant Lines:	3422

---

💛 - Coveralls

[RReverser]

@bheisler I've fixed Clippy warnings, builds should be passing now.

[RReverser]

Seems to pass except for coverage changes (I'm not sure if these numbers are actually fair / important though).

[bheisler]

Hey, thanks for the pull request!

Yeah, don't worry about the coveralls numbers. They don't seem to reflect reality and I'm not really sure why. I should probably figure that out and fix it or drop the coveralls integration.

Anyway, I'll try to give this a proper code review soon.

[bheisler]

Looks good to me. Thanks again!