Disable TypeScript incremental build

It seems that incremental build doesn't work correctly with ts-node or
ts-jest. Sometimes, probably after unit test failure, lib directory
contains src and test directories, but only content of src should be
there, because baseUrl is set to "src" in tsconfig.json.

Disabling the incremental build fix this issue. Since this project is
quite small I don't think disabling this feature will have major impact
on build time.

Following issue in ts-node project might be related:
TypeStrong/ts-node#817

tsconfig.json

@@ -2,11 +2,9 @@
   "extends": "@tsconfig/node10/tsconfig.json",
   "compilerOptions": {
     "baseUrl": "src",
-    "incremental": true,
     "declaration": true,
     "sourceMap": true,
-    "outDir": "lib",
-    "tsBuildInfoFile": "./build/tsconfig.tsbuildinfo"
+    "outDir": "lib"
   },
   "include": [
     "src/**/*"