Add better parser errors (#1553)

Old SVGO errors were not very helpful. Packages like cssnano
(postcss-svgo) had to deal with a lot of issues which are hard to debug
with old errors.

```
Error: Error in parsing SVG: Unquoted attribute value
Line: 1
Column: 29
Char: 6
File: input.svg
```

New errors are more informative and may solve many struggles

```
Error: SvgoParserError: input.svg:2:29: Unquoted attribute value

  1 | <svg viewBox="0 0 120 120">
> 2 |   <circle fill="#ff0000" cx=60.444444" cy="60" r="50"/>
    |                             ^
  3 | </svg>
  4 |
```

test/cli/cli.test.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const { spawn } = require('child_process');
+const stripAnsi = require('strip-ansi');
+
+test('should exit with 1 code on syntax error', async () => {
+  const proc = spawn('node', ['../../bin/svgo', 'invalid.svg'], {
+    cwd: __dirname,
+  });
+  const [code, stderr] = await Promise.all([
+    new Promise((resolve) => {
+      proc.on('close', (code) => {
+        resolve(code);
+      });
+    }),
+    new Promise((resolve) => {
+      proc.stderr.on('data', (error) => {
+        resolve(error.toString());
+      });
+    }),
+  ]);
+  expect(code).toEqual(1);
+  expect(stripAnsi(stderr))
+    .toEqual(`SvgoParserError: invalid.svg:2:27: Unquoted attribute value
+
+  1 | <svg>
+> 2 |   <rect x="0" y="0" width=10" height="20" />
+    |                           ^
+  3 | </svg>
+  4 | 
+
+`);
+});